[Vulnavia]

The ON position is ACC with the engine running, so I don't get the point of the question.

 

[2ndHonda]

So say I have driven somewhere and I want to park and continue listening to the radio with the engine off for example.. in a keyed car you turn it back on position. Can I do that in a button start car?

 

[marty1]

So say I have driven somewhere and I want to park and continue listening to the radio with the engine off for example.. in a keyed car you turn it back on position. Can I do that in a button start car?

I checked the 2015 Owners Manual and the Start/Stop button logic is the same as my 5th Gen. See diagram below from your manual.
If you press and release the Start/Stop button once BEFORE you shift to Park, the engine will stop and power shifts seamlessly to accessory mode. This is indicated by the small dark grey "up" arrow (see legend at bottom of diagram).

On US models, if you then shift to Park, all power shuts off. Indicated by the larger light grey "up" arrow.
On Cdn models if you then shift to Park the Acc power remains On.

On US models if you do this and want to stay in Acc mode for awhile, you need to keep your foot on the brake pedal or apply the parking brake to ensure the vehicle doesn't roll. Make sure you shift to Park before leaving.

 

[2ndHonda]

Thank you @marty if I can get the CRv from my wife I will try that out.